In chemical processing and other industries, the manufacture, transportation, storage, and other operations involving chemicals, combustible fluids, and other hazardous materials necessitates containment and containment assurance of such materials. Increasingly, environmental and safety regulations and laws address hazardous fluids containment and containment assurance. Accordingly, there is a continuing need for containment systems and devices that comply with the laws and the regulations.
One prior art leakage containment device provides a leakage collecting tank positioned below a component to collect leakage from the component. For example, the tank can comprise a well or other such structure open at the top. A disadvantage is that dirt, rain, snow, and ice may also accumulate in the tank, obscuring the existence of a leak. Furthermore, solvent leaks can go undetected by virtue of the open tank construction allowing atmospheric evaporation, which can also create environmental release problems.
U.S. Pat. No. 4,850,389 describes a device and method for monitoring an enclosed cavity for leakage. A ground seal and a pressure seal define a cavity that is provided with a pneumatic fitting. The cavity is pressurized and monitored by a detachable pressure monitoring gauge. A decrease in monitored pressure can indicate the existence of a leak either through the ground seal or through the pressure seal. A shortcoming, however, is that it does not indicate which seal is leaking if just one of the seals leaks and therefore would not provide adequate containment assurance for a system having a primary seal and a secondary, backup containment seal. Also, the initial pressure charge can leak out, providing a false indication of seal failure. Another drawback is that the cavity pressure can vary depending on temperature.
U.S. Pat. No. 4,424,973 describes a leak indicator that comprises a plug having a liquid sensor electrically connected to an indicator instrument. The plug leak indicator is connected to a channel that at an opposite end terminates at a sealing ring. Leakage of liquid past the sealing ring into the channel activates the sensor to generate an electrical signal to the instrument. A shortcoming of this device is that it is relatively complex and expensive, particularly for applications in which leak detectors are required to be installed in a plurality of locations.
U.S. Pat. No. 4,453,411 describes a pressure memory device for trapping fluid in a chamber to register and retain the highest or lowest pressure occurring in a fluid-containing system. The device comprises a manifold having a through bore with a check valve disposed therein and a second bore intersecting a third and a fourth bore. Two of the bores are sealed with plugs and a second valve is secured in a bore. The device can be used in conjunction with a standard pressure gauge to obtain the highest or lowest system pressure. The device, however, is complex and provides just a single point reading of maximum system pressure.
It is an object of the invention to solve one or more of the above-stated problems.